Dan Bryant pushes his feet down on the funky piece of plywood, sinking into an upper Rogue River riffle exactly by design.

His hands grip rope handles as he floats downstream, triggering tension on the long bungee cord attaching his riverboard to the bank.

When the tension hits its climax, Bryant and his board shoot forward at close to 40 mph and he digs the corner of the board into the river to throw a roostertail splash forward.

"That was probably a 50-footer," says Bryant, 45, of Medford.

That's also 10 points on the National River Board Association score sheet Bryant devised 21 years ago, but only a few family members watching from shore notice.

"It's ultimately you and the water," Bryant says. "Once you have it, it's yours to do anything you wish."

Bryant's been selling that image of riverboarding for 30 years now. And for the life of him, he can't believe the rest of the watersports world hasn't bought in.

This niche sport that traces its roots to the upper Rogue has yet to crack the extreme sports crowd despite Bryant's lifelong effort to introduce it to envelope-pushers who play on water.

He's still waiting for that one endorsement check, that one national demonstration, that one shot at showing adrenaline junkies now on skateboards, snowboards and water skis what riverboarding has to offer.

Bryant believes that's all riverboarding needs to be the next hot X Games competition.

"Once people find this, come to this and legitimize it as a sport, it'll give every watersport a run for its money," Bryant says.

"This could even be done on the Olympic level," he says.

Still, only a handful of riverboarders sprinkled around the Pacific Northwest have drank Bryant's Kool-Aid. A few German tourists who stumbled onto Bryant and his riverboard during a trip on the Rogue 17 years ago brought the sport to Europe, where its mild popularity ranks higher than in the United States.

"It's a sport trapped in this little niche," he says.

This weekend was supposed to be a breakout time. Bryant planned to have a representative from the Guinness Book of World Records on hand at his riverboarding playground on the Denman Wildlife Area to verify world records in dozens of trick categories.

Riders from throughout the Northwest were to attend.

But Bryant, a landscaper by day, couldn't raise the $700 needed to get Guinness to town.

"If I was born with a silver spoon in my mouth instead of a shovel, it would be a lot further along," he says.

Had it happened, many of those records likely would have fallen to Bryant's son, 20-year-old Andy Bryant of Medford.

Andy Bryant grew up on a riverboard, and his command of this craft is unmatched here.

He can do double and triple spins as the board hurtles forward through the riffle. Front flips, back flips, toe drags and full submersions are part of a repertoire he exhibits during 5- to 10-minute stints on his board.

If riverboarding were snowboarding, Andy Bryant would be the Flying Tomato of his sport. But it's not, so he's not.

But he's certainly thought about it, picturing it in his mind.

"Oh, definitely," he shrugs. "That would be nice."

The Bryants set up shop on what they call the Modoc Hole at Denman regularly. They boarded for 21 straight days before the Jackson County Fair. Their record is 57 straight days of boarding.

Bryant sells riverboarding set-ups for about $300. You get a bungee, a shore anchor and a board. He sells a small handful a year.

Bryant has produced safety guides, formed his association, led an expedition throughout the Northwest and set up satellite chapters throughout the region. He's even introduced riverboarding to Wikipedia.

And one of these days, he says, someone will step up and the next thing you know riverboarding will be on cable television some Saturday morning. Then it'll be on to the X Games, eventually to the Olympics, Bryant says.

And film crews will venture back to the Modoc Hole at Denman, where riverboarding started.

"I've literally driven tens of thousands of miles promoting this sport, and my journey's not over," he says. "It'll happen. You'll see."

Reach reporter Mark Freeman at 541-776-4470, or email mfreeman@mailtribune.com. Follow him on Twitter at http://twitter.com/MarkCFreeman